Fig. 5.

NO₂⁻ consumption by wild-type and mutant strains of M. catarrhalis O35E. Cell suspensions of the wild-type strain, the norB mutant, the nsrR norB mutant, and the aniA norB mutant in BHI medium supplemented with 5 mM NaNO₂ were monitored for the presence of NO₂⁻ using the Griess reaction. The data shown are the averages of results from three independent experiments, with standard errors indicated.